Sort the mixtures below under the correct headings: Vinegar, mayonnaise, fizzy drink, yoghurt, jello, seawater, apple juice, cement, whipped cream, cheese, paint, sand and water, chalk and water, stainless steel, vegetabke soup, peanut butter, muddy water, coco pops and milk

Solution
Small particles, can pass through filter paper, looks same throughout. Cannot be filtered. Doesn’t settle Suspension
Particles large enough to be seen with naked eye, settles when left. Can be filtered Colloids
Intermediate between solutions and suspensions. Cannot be filtered, includes foams and gels. Scatter light.

the answer for sodium is 0.186

the answer for rubidium is 0.251

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.